how to install python 3 in ubuntu 16.04
Server install image
The server install image allows you to install Ubuntu permanently on a computer for use as a server. It will not install a graphical user interface.
There are two images available, each for a different type of computer:
64-bit PC (AMD64) server install image
Choose this to take full advantage of computers based on the AMD64 or EM64T architecture (e.g., Athlon64, Opteron, EM64T Xeon, Core 2). If you have a non-64-bit processor made by AMD, or if you need full support for 32-bit code, use the i386 images instead. Choose this if you are at all unsure.
root@Mitaka-lab:~# apt-get install python3.4 python3.4-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'libpython3.4-minimal' for regex 'python3.4'
E: Unable to locate package python3.4-dev
E: Couldn't find any package by glob 'python3.4-dev'
E: Couldn't find any package by regex 'python3.4-dev'
root@Mitaka-lab:~# python --version
root@Mitaka-lab:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.1 LTS
root@Mitaka-lab:~# which python